1. Field of the Invention
The present invention relates to an exercise machine which may be used for the execution of training exercises and more particularly to an exercise machine providing a greater versatility of exercises, a greater freedom of exercising movements, an easier gripping, an easier overall use, and a longer durability of components.
2. Description of Related Art
Various exercise machines for the execution of physical exercises are well known in the art and include machines that utilize a weight stack and a pulley system to provide resistance to an exercise movement. A typical exercise machine has a frame, a means to provide resistance mounted on the frame, and a means for interacting with a user, such as a gripping element. Pulleys and cables are most commonly used to connect the means for providing resistance to the means for interacting with a user.
Cables used for that purpose may have a braided core made of textile or metallic material and covered with a sleeve made of braided plastic material. Cables with the textile core are generally more flexible than cables with metal core, but the former often exhibit excessive plastic elongation during use, requiring frequent adjustments of the moving parts of the machine so as to remove the excess cable length caused by wear.
When the means for interacting with a user is a handle, it may have an elongated body and at least one eyelet connected rigidly to the elongated body. The flexible cable is passed through to the inside of the eyelet and locked by means of a knot, but more frequently by a crimped loop, to ensure greater security of the connection. In other cases, the handle is positioned on route of the flexible cable, and is therefore connected to the flexible cable by means of respective end sections which may have eyelets for crimped loops, typically one for each segment of the cable.
In other designs, the handle terminates with end sections, each one of which has housing with a transverse section sufficiently large to accommodate the end of the corresponding segment of the cable knotted onto itself or having a restraining component. The cable is placed in communication with the outside by means of a conduit which, similarly to the ordinary bicycle brake levers, has a transverse section of a size substantially identical to the transverse section of the cable, in order to make the holding function of the end of the handle effective.
By virtue of what is described above, each length of cable housed inside the conduit leading to the housing for the knot or the restraining component is stressed tangentially by the end of the handle. The cable is therefore bending-deformed in addition to being placed in frictional contact with the edge of the handle as illustrated in FIG. 5. The bending deformation may arise due to linear or rotational movements depending on the type of training carried out by the user. The consequence of the frictional contact is frictional wear of the flexible cable and of the sleeve. The consequence of the bending deformation is fatigue of the cable fibers, typically followed by the unexpected breakage of the cable. In addition, the fatigue of the cable fibers may or may not be preceded by work-hardening of the fibers depending on their structure, but is rarely preceded by a warning signal of the breakage itself.
Failure to keep a watch on the current condition of the cable is a frequent cause of unexpected machine stoppage caused by an unexpected breakage of the cable attached to the handle. Such breakage can also be the cause of injury to the user or to anyone else in the proximity to the exercising machine while it is in use. This situation happens frequently in functional resistance exercise machines, because the movement which can be imparted to the implement in such machines can be executed on any trajectory, which trajectory may vary according to the type of training which the user intends to execute. The possibility of unexpected breakage in conventional exercise machines thus requires the condition of the cable to be frequently monitored, in order to arrange for its replacement prior to critical fatigue conditions.